These findings have been used to question the need for adjuvant radiation in the treatment of pancreatic malignancies.

The US Intergroup/RTOG 9704 trial (Regine WF, et al. IJROBP. 2006;66(3):S23(#42)) randomized 538 patients with pancreatic andeocarcinoma following resection to Gemcitabine followed by chemoradiation followed by Gemcitabine or 5-FU followed by chemoradiation followed by 5-FU.

Although RTOG 9704 cannot be directly compared to CONKO-001, these two trials can allow for a debate of the role for radiation therapy in patients with pancreatic cancer, provided differences in patient characteristics of the two trials are examined. Specifically, the CONKO-001 trial required post-resection CA 19-9 levels to be less than 2.5 times the upper limit of normal (approximately 90 U/ml), while RTOG did not have an exclusion criteria based on CA 19-9.

Three-year overall survival for patients with CA 19-9 <90U/ml was 33%, significantly higher than the 2% for patients with levels >90 U/ml (p<0.0001).

For comparison, the median and 3-year overall survival reported in the CONKO-001 trial among patients in the gemcitabine arm were 22.1 months and 34%, respectively, while the median and 3-year overall survival seen in the RTOG 9704 trial among patients in the Gemcitabine arm with pancreatic head tumors, a CA 19-9 ≤90 U/ml, and a RTQA score per protocol were 25.2 months and 46%, respectively.

Author's Conclusions

RTOG 9704 analysis demonstrates that post-resectional CA 19-9 values of >90 U/ml are associated with a significant decrease in survival among patients treated with adjuvant therapy.

CA 19-9 levels were found to be the most important predictor of survival, while nodal involvement and RTQA score were also demonstrated to influence survival. No other factors significantly impacted survival.

RTOG 9704 supports the continued administration of adjuvant radiation among patients with pancreatic adenocarcinoma in future trials, especially among patients with elevated post-resectional CA19-9 values.

Clinical/Scientific Implications

The RTOG trial supports the continued administration of radiation therapy in the adjuvant setting for patients with pancreatic adenocarcinoma. CA 19-9 in this study was clearly demonstrated to be an important prognostic factor among these patients, with post-resection values >90 U/ml correlating with significantly worse survival. This is not surprising as high CA 19-9 level after resection signifies either residual disease in the pancreatic bed and nodal region or subclinical metastatic disease. These results indicated that future adjuvant therapy trials for patients with pancreatic adenocarcinoma should stratify patients according to post-resectional CA 19-9 levels.

Partially funded by an unrestricted educational grant from Bristol-Myers Squibb.

Oct 17, 2011 - In patients with resected stage II and III colon cancer treated with identical adjuvant therapy, blacks have worse overall and recurrence-free survival than whites, but a similar recurrence-free interval, according to a study published online Oct. 12 in the Journal of the National Cancer Institute.